The present embodiments relate to timing of displayed images and scanning. The video frame rate output by many ultrasound imaging systems is fixed. For example, images are output at 30 Hz or 60 Hz to simplify the conversion to NTSC standard video signals required by videocassette recorders. Matching the video frame rate to the frame rate used in common applications simplifies recording ultrasound scans. Off-the-shelf parts may be used for the video generation in the ultrasound system as well.
To accommodate the fixed video frame rate, the acoustic frame rate is set at a fixed integer ratio with the video frame rate. The transmit and receive beamformation scan rate is fixed. The ratio may be a non-integer ratio in some systems. A large buffer memory is used for frame rate conversion from the acoustic frame rate to the video frame rate. However, the buffer memory and processing overhead for rate conversion may be undesired due to cost, size, and/or power requirements.